The invention relates to a fuel injection valve according to the preamble of claim 1.
In fuel injection systems, fuel is injected under high pressure through a fuel injection valve into the combustion chamber of an internal combustion engine.
In DE 30 14 958 A1 a fuel injection valve is disclosed which has a nozzle body with a central guiding bore in which a nozzle needle is carried. The nozzle body is configured as a perforated nozzle. The axial movement of the nozzle needle opens the valve, which is formed by the sealing edge of the nozzle needle and the valve seat in the nozzle tip of the nozzle body. At the needle tip of the nozzle needle a step is created in order to prevent the valve seat diameter from being reduced due to wear.
When the valve opens, fuel flows into the nozzle tip and through the injection holes in the nozzle tip, so that the nozzle needle can perform movements aimed laterally of its axis caused by the fuel pressure and the flow of the fuel, resulting in an irregular injection into the combustion chamber of the internal combustion engine.
The task of the invention consists in reducing movements of the nozzle needle aimed radially to the nozzle needle axis occurring when the valve is opened and in improving the shape of the injected jet.
The task of the invention is accomplished by the features of the independent claims.
Advantageous embodiments of the invention are given in the subordinate claims.
In the invention a nozzle needle is guided in the central guiding bore of a nozzle body. The nozzle needle has a circumferential sealing edge which forms together with the conical valve seat of the nozzle body a closable and pressure-proof seal which controls by the axial movement of the nozzle needle the flow of fuel to the injection holes in the tip of the nozzle body. In the truncatoconical extremity of the nozzle needle a circumferential groove is provided at which, when the fuel injection valve opens, a pressure equalization is established by which a force acting radially on the nozzle needle is produced which opposes a radial deviation of the nozzle needle and thus guides it axially.
Advantageously, the groove is disposed at the level of the injection holes in the nozzle tip of the nozzle body, so that the shape of the injected jet is improved.